A technique for controlling in-home devices from a remote terminal through the Internet has been conventionally developed. There is known, for example, a method for displaying an electronic program guide (EPG) stored in a server on a WEB screen, thereby allowing a user to freely select and program using a terminal device such as a personal computer (PC) or a cellular telephone (see, for example, Japanese Patent Laid-Open Publication No. 2001-145140).
A conventional example of a remote control method for controlling a target device from an external device through the Internet will be described with reference to FIG. 6.
As shown in FIG. 6, an application server 80, a mail server 90, and devices 91a, 91b and 91c are connected to one another through the Internet 100.
A terminal device 10 is a terminal device such as a PC or a cellular telephone which enables a user to view a WEB screen through the Internet. The server 90 is a mail server held by a provider to which the user generally subscribes. The devices 91a, 91b and 91c are devices operable to perform timer recording.
The application server 80 includes means for storing program data for performing a timer recording, and includes functions to generate timer recording data while referring to the stored program data based on a user's operation, and to transmit this timer recording data as an electronic mail (e-mail).
The mail server 90 has functions to receive an e-mail transmitted from one user, to store the received e-mail, and to send the e-mail to the other user. The mail server 90 is often referred to as “mail box”.
Each device 91a, . . . has functions to receive the e-mail from the mail server 90, to detect the timer recording data from the received e-mail to store the detected timer recording data. Each device 91a, . . . also has functions to determine whether the timer recording data is stored, and to execute and manage the timer recording.
When receiving, for example, an instruction for timer recording from the terminal device 10 based on the user's operation, the application server 80 generates an e-mail including the timer recording data and transmits the e-mail to the mail server 90 of each provider to which the user subscribes. The device 91a, . . . regularly checks whether the corresponding provider receives the e-mail, thereby extracting the timer recording data from the received e-mail to control a timer recording operation based on the timer recording data. This operation will now be described specifically.
When receiving a display request based on the user's operation from the terminal device 10, the application server 80 converts the program data into data in an HTML (Hyper Text Markup Language) format so that user can browse the stored program data on the WEB screen and a display on which the user can easily operate can be provided. The application server 80 then transmits the HTML format data to the terminal device 10. The user can select a program while viewing a content displayed by the terminal device 10. Data indicating a user's selected item is transmitted to the application server 80 which then analyzes the data. If detecting that the data is the timer recording instruction, the application server 80 generates timer recording data. That is, the application server 80 generates the timer recording data while referring to data indicating the user's selected item and to the stored program data. This timer recording data normally includes data such as a recording start time, a recording end time, and a channel number. The application server 80 converts the timer recording data into data in an e-mail format, and transmits the data in e-mail format to a mail address (mail server 90) designated by the user. The mail server 90 stores the received e-mail. The device 91a receives the e-mail from the mail server 90 at an arbitrary timing, extracts the timer recording data from the received e-mail, and controls a timer recording operation based on the timer recording data.